Technical Field of the Disclosure
The present embodiment relates in general to abrasive blasting equipment for preparing metal surfaces for painting; and more particularly to a dustless blaster that eliminates the need for a pressurized tank and is adaptable for installation in any location with a compressed air supply.
Description of the Related Art
Abrasive blasting is the operation of forcibly propelling a stream of abrasive material against a rough surface under high pressure to smooth the rough surface and to remove surface contaminants. In conventional abrasive blasting methods, the abrasive material used is dry and finely-divided. In these methods, large amounts of dust containing silica are emitted into the atmosphere. If inhaled, this dust can stick to the lung tissue potentially causing severe health problems.
For example, one of the existing conventional blasting methods provides a light weight mechanism that can be conveniently carried in the hand of the user with a pneumatic air gun through which a high velocity air stream can flow, thereby delivering a stream of dry granular abrasive material. In this apparatus, the abrasive material moves at a low velocity when compared with the intended high velocity of an air stream, to prevent undue wear upon the metallic surfaces of the conduit through which the material passes when discharged. In this method, as stated above, a large amount of dust is emitted into the atmosphere.
In order to overcome the drawbacks of the aforementioned method, dustless abrasive blasting methods have been developed. In the dustless abrasive blasting method, an abrasive element is entrained in a pressurized liquid flow and then directed through a nozzle. Current dustless blasters must have a pressurized system that requires EPA/OSHA standard pressurized tanks, thereby requiring more time and energy to set up and operate. Dustless methods are traditionally very expensive and difficult to set up.
Another existing blasting apparatus includes a pressure vessel adapted to contain a particulate blasting medium and a liquid. The vessel includes an inlet and a bottom outlet. The interior of the vessel communicates via its bottom outlet with an opening in a conduit through which an entraining pressurized mixture of media and fluid can be fed from a pressurized gas source. A pressurizing device is provided to pump liquid into the vessel and through the bottom outlet. Immediately upstream of the opening in the conduit is located a venturi so that the velocity of the pressurized gas is increased as it passes over the opening thereby increasing the quantity of particulate blasting medium entrained by the gas. However, the pressure vessel of the apparatus is traditionally very expensive and difficult to set up.
Yet another method describes a fluid-jet-abrasive device having a fluid-jet gun with a trigger adapted to operate a pressure-control valve, to allow fluid to flow through and pass out of the spray-nozzle of the gun under extremely high pressure and velocity. The fluid is under pressure supplied through an interconnected flow system with a water-tank reservoir, a pumping unit coupled at one end to the water tank and at the opposite end to the pressure inlet of the gun through a recirculating conduit system. The gun includes a separate inlet port through which various types of abrasive materials are passed and mixed with the fluid to be sprayed under high pressure. The abrasive material is stored in a tank with a material-flow regulator attached to automatically control the amount of the abrasive material delivered to the gun. In addition to sharing drawbacks with some other conventional systems is the lack of any feature that provides for rust inhibition.
Therefore, there is a need for a dustless blaster that would provide paint stripping, rust removal, and metal preparation for paint with minimal effort. Such a dustless blaster would eliminate the need for a pressurized tank. It would be cost effective and adaptable to being setup in any location with an air supply. Further, such a needed dustless blaster would use silica free media and would function with air and water supply. In addition, this blaster would utilize a venturi to siphon water and media which would automatically mix within an exterior nozzle to provide a rust inhibiting coating. The present embodiment overcomes existing shortcomings of dustless blasters by accomplishing all of these objectives.